Overview

Reported declines of many birds breeding in North America have stimulated interest in avian population trends and mechanisms driving those trends (DeSante and George 1994). The North American Breeding Bird Survey suggests that landbird populations in Pacific Northwest lateseral forests appear to be in serious decline (Sauer et al. 2003), and data from the national parks are particularly important for teasing out possible causes. Quantitative survey data for bird habitat usage and abundance at Lewis and Clark National Historical Park are currently lacking. Existing presence/absence data are insufficient for tracking population changes over time, or for gauging the effects of any future management actions that may alter habitat conditions. These goals require species-specific density estimates.